Telephone-transmitter.



Patented Feb. 20 I900.

A. STRUIBERG.

TELEPHUNE TRANSMITTER.

(Application filed. Nov. 10, 1899.)

(No Model.)

UNITED STATES PATENT FFFICE.

ALFRED STROMBERG, OF CHICAGO, ILLINOIS.

'TELEPHONE-TRANSMITTER.

SPECIFICATION forming part of Letters Patent 0. 643,830, dated February 20, 1900. Application filed November 10, 1899. Serial No. 736,475. (No model-i To all whom it may concern.-

Be it known that L ALFRED STROMBERG, a citizenof the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Telephone Transmitters, (Case No. 2,) of which the following is a full, clear, concise, and exact description, reference being had to the accompanying'drawings, forming a part of this specification.

My invention relates to telephonic apparatus, and has for its object the construction of an improved form of transmitter which is adapted by varying the resistance of a transmitter-circuit, including a battery, to propagate voice-currents to suitable receivers.

My invention has for one object the construction of an improved battery-transmittedwhich, while dependingfor its operation upon variation of resistance in the circuit incl udin g the same occasioned by sound-waves, does not depend upon variation in pressure between electrodes included in the transmitter-circuit. To this end my invention in its preferred embodiment comprises a movable element orelectrode adapted to be actuated by soundwaves, the movement of this element being so controlled that while it is adapted to vary its position with relation to the engaging electrode it in no-wise exerts a varying pressure upon nor displaces the same.

My invention in its preferred embodiment comprises a revoluble electrode having a fixed axis of rotation and arranged to be rotated upon its axis by means of sound-waves, a second electrode being in engagement therewith,

the area of contact between the electrodes be mitter-circuit. Fainter sounds therefore haveless current to cause the propagation of elecmirably adapted to carry out'this second fea-.

ture of my invention.

I will describe my invention more particularly by reference to the accompanying drawings, illustrating the preferred embodiment thereof, in which- Figure 1 is a plan'view of myimproved' transmitter suitably supported in place. Fig. i? is a side viewof the apparatus shown in ig. l. of thetransmitter. Fig. 4='is a view in crosssection of the transmitter on line 4 4 of Fig. 1., circuit connections of the transmitter being indicated diagrammatically. Fig. 5is a longitudinal sectional elevation on line 5 5 of Fig. 1. Fig. 6.is a view of the revoluble elem trode separated from its supporting-shaft. Fig. 7 is aplan view of the receptacle for containing the comminuted electrode, the revoluble electrode being removed.

Like parts are indicated by similar letters of reference throughout the different views.

In practicing my invention I take pains to prevent variation in pressure between electrodes of the transmitter-circuit, and the construction illustrated is well adapted to this end. Oneof the electrodes is preferably in Fig. 3 is a longitudinal elevation plush, the plush packing surrounding the carbon granules upon four sides, the carbon v being preferably inclosed .in a rectangular space. A supporto is rigidly secured in'positiou upon the brace-piece d or other suitable mounting, the plush packing being glued in place within the cavity of this support, as

shown. most clearly in Figs. 4 and 5. The

portion of the support holding the carbon is metallic, the carbon granules being in direct electrical contact therewith. The support is preferably ext-ended longitudinally in both directions from the carbon electrode and is provided with a binding-screw for other suitable means for connecting a transmitter-conductor therewith, whereby said carbon is made to constitute an electrode. Insulating-plates g are rigidly secured to the ends of the support 0, each plate supporting a bearing-screw h,projectinginwardly. Ashaftiisjournaled at its ends upon the screws h h, this shaft supporting a cylinder formed in sections of metal and insulating material, one half of the cylinder It being preferably formed of insulating fiber,while the otherhalfl is preferably formed of brass. Tllese parts of the cylinder may be suitably secured together upon the shaft by means of screws. The metal member I is preferably gold-plated. This composite cylinder is preferably so disposed that theinetal and insulating portions thereof are both normallyin contact with the carbon granules or other comminuted material, the plush packing employed to confine the carbon in place surrounding the lower portion of the cylinder to retain the carbon in uniform contact with the cylinder as a whole. I have showna flexible wire m att-achedpto the shaft of the cylinder, the shaft being in metallic contact with the part 1.

One of several transmitter-circuits that may be employed in connection with my invention is illustrated in Fig. 4, where one terminal of the battery n is connected with the support 0 and the carbon a, while the other terminal of the battery is adapted to be united with the metallic portion Z, a primary coil 0 being adapted for connection beceiver is removed from the switch-hook. The

switch-hook also serves to close the transmitter-circuit when the receiver is removed. I preferably actuate the revoluble electrode by the mechanism illustrated. I employ a diaphragm 25, located at the rear of a mouthpiece it, and arm 2; being secured, preferably, to the central portion of the diaphragm at. one end, this arm being provided with a recess or aperture at its other end, whichreceives the sharp point of a pin w, extending radially from the shaft 1', this pin serving the function of a crank, as will be more readily understood by reference to Fig. 4. A move- .ment of the diaphragm is accompanied by a longitudinal motion of the arm or link 1;, which in turn, by its engagement with the pin 10, will cause a rotation of the cylinder. When the arm is pressed in by the action of the sound-waves, the composite cylinder will be rotated in a clockwise direction, thereby decreasing the area of contact between the metallic portion Zofthe cylinder and the carbon or other comminuted material engaging the same, whereby the resistance of the cir-.

.the sound-waves, sufficient of the carbon is always maintained in contact with the part I to prevent the resistance from being too great for the proper operation of the transmitter.

While I have herein shown a well-known transmitter-circuit and have illustrated the preferred embodiment of my invention in connection therewith, it is obvious that changes may readily be made without departing from the spirit of my invention, and I do not therefore wish to be limited to the precise construction and arrangement shown nor to the use of comminuted carbon as an electrode. Iam enabled by means of my invention to overcome serious objections herctofore.existing against transmitters employing comrninuted material as an elect-rode. Hereto fore the comminnted electrode was liable to pack, especially where carbon was employed. Moreover, it was diflicult to secure and maintain proper relative adjustment between the diaphragm and the comminuted electrode. Accidental buckling of the diaphragm in transmitters of this class and in variablepressnre transmitters was very liable to throw the transmitter out of adjustment. By means of the transmitter of my invention it is not necessary to secure and maintain any particular adjustment of the transmitter.

While I have shown the comminuted electrode as being stationary and the electrode engaging the same as being revoluble, Ido not wish to be limited to the precise structure shown nor to the employment of a local transmitter-circuit.

Having thus described my invention, I claim as new and desire to secure by. Letters Patent 1. In a telephonic transmitter adapted for operation by sound-waves, the combination with two electrodes adapted for inclusion in ,a transmitter-circuit, of means for varying the contact between the electrodes without varying the pressure between the electrodes to increase the resistance or the transmittercircuit upon an increasein force of the soundwaves, and to cause a relativelydess resistance in the transmitter-circuit upon a decrease in the force of the sound-waves, substantially as described.

2. The combination with a transmitter-circuit including a battery and engaging electrodes of a transmitter, of means-for decreasing the area of contact between the electrodes of the teansmitter upon an increase in the 643,830 v I a force of 'the sound-waves, and for eflecting a relative increase of the area of contact between the electrodes upon a' decrease in the force of the sound-waves without varying the pressure between the electrodes, substanthereof through the action of sound-waveswithont varying the pressure between the:

electrodes, substantially as described.

5. In a telephonic transmitter, the combi-' nation with a revolubleelectrode, of asecond electrode in contact therewith, the said revoluble electrode being confined to a fixed axis of rotation, a diaphragm; and a connection between the diaphragm and the revoluble electrode to effect the rotation thereof through the act-ion of sound-waves, substantially as described.

6.- In a telephonic transmitter, the combination with a revoluble electrode, of a second electrode in contact therewith, a diaphragm, an arm '0 engaged between the diaphragm and the revoluble electrode serving to vary contact between said electrodes withoutvarying the pressure between them, whereby upon an actuation of the diaphragm, the revoluble electrode is actuated-to vary the resistance in the transmitter-circuit, substantially as described. v

7. In a telephonic transmitter, the combination with a revoluble element formed in sections of metal and insulating material, of a second electrode adapted for engagement with the said metal and insulating material, the metal constituting an electrode of the transmitter, and means for eifecting the rotation of the said element to vary the area of contact between the revoluble electrode and the electrode engaging the same, substantially as described. f

8. In a telephonic transmitter the combination with a revoluble element formed, in sections of metal and insulating material, of a second electrode adapted "for engagement with the said metal and insulating mate ifial,

the metal constituting an electrode-of-the; transmitter, and means for rotating the ele-' ment to decrease the area of contact between the revoluble electrode and the engaging nation with a revoluble element formed in sections of metal and insulating material, of a second electrode adapted for engagement with the said metal and insulating material, the metal constituting an electrode of the transmitter, a diaphragm, and a connection between the diaphragm and the said revoluble element for efiecting-its rotation, substantially as described.

' '10. Inatelephonictransmitter, the combination with a revoluble element formed in -sections of metalvand insulating-material, of

a second electrode adapted forengagemeut with the said metal and insulating material, the metal constituting an electrode of the transmitter, a diaphragm, an arm 12 interposed between the diaphragm and the revoluble element, anda pin to provided upon the revoluble element and engaging the contigu ous end of the arm n, substantially as described.-

. 11. In a telephonic transmitter, the combination with an electrode in the form of comminuted material, 0% a revol uble element having uniform engagement with the said comminuted material, a packing for securingthe comminuted material in place, the said revolubleielementcomprising a portion of insulating material and a metal portion, both adapted for engagement with the com minuted material, the said metallic portion constitutand means for-eifecti-ng a rotation of the said element ftovary'the area of contact between the revoluble electrode and the comminuted nation with an electrode in the form of comminuted material, of arevolubleelemen't having uniform engagement with the said comminuted material, a packing for securing the comminuted material in place, the said revoluble element comprising. a portion of' insulating material and a metallic portion, both ing the other eiectrode of the transmitter,

IOO

adapted for engagement with the comminu ed mat-erial,the said metallic portion constituting the other electrode of the transmitter,

and means for decreasing the area of contact between the revoluble electrode and the com minuted material upon an increase in the force of the sound-waves and for efiecting a relative increase of thearea of contact between the revoluble electrodeand the comminuted material upon a decrease-in the force "of the sound-waves, substantiallyas described.

- .13. In a telephonic.,transmitter the. combi nation 'with'an electrode-in. the form of comdiaphragm, a pin to extending from the shaft of the revoluble element, andan arm '0 interposed between the diaphragm and the said pin, substantially as described. 14. In a telephonic transmitter, the combination with 'an electrode in the form of commiuuted material, of a revoluble element having uniform engagement with the said comminuted material, -a packing for securing the comminuted material, in place, thesaid revoluble element vcomprising a portion of insulating material and a metallic portion, both adapted for engagement with thecomminuted material, the said metallic portion constituting the other electrode of the transmitter, a diaphragm, and an arm 1; interposed between the diaphragm and the revoluble element to effect the rotation thereof, substantially as described.

15. In a telephonic transmitter, the combination with an electrode in the form of comminuted material, of a revoluble element having uniform engagement with the said comminuted material, a packing for securing the comminuted material in place, the said revoluble element comprising a portion of insulating material and a metallic portion,

both adapted for engagement with the comminuted material, the said metallic portion constituting the other electrode of the transmitter, a diaphragm, and an arm '11 intereffect a relative increase of the area of contact between the revoluble electrode and the comminuted material upon a decrease in the force of the sound-waves, substantiallyas described.

16. In a telephone-transmitter, the combination with an electrode, of a second comminuted electrode and means for efiecting the rotation of one of the electrodes through the agency of sound-waves, substantially as described.

17. In a telephone-transmitter, the combination with an element formed in sections of metal and insulating material, the metal .con-

stituting an electrode of the transmitter of a second comminuted electrode in engage ment with the metal and insulating portions of the aforesaid element, and means foreffectiug the rotation of one of the electrodes through the agency of sound-waves, substantially as described.

18. The combination with a transmittercircuit including a batteryand-the electrodes of a transmitter which have sliding contact in the operation of the transmitter, of means for decreasing the area of contact between the electrodes of the transmitter upon an increase in the force of the sound-waves and. for eifecting a relative increase of the area of contact between the electrodes upon a decrease in the force of the sound-waves, substantially as described.

In witness whereof I hereunto subscribe my name this 78th day of November, A. D. 1899.

ALFRED STROMBERG.

Witnesses:

Omanns A. BROWN, Gnoaon L. Canoe. 

